From: Thomas Garnier <thgarnie@google.com> To: Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>, "H . Peter Anvin" <hpa@zytor.com>, Borislav Petkov <bp@suse.de>, Joerg Roedel <jroedel@suse.de>, Dave Young <dyoung@redhat.com>, "Rafael J . Wysocki" <rafael.j.wysocki@intel.com>, Lv Zheng <lv.zheng@intel.com>, Thomas Garnier <thgarnie@google.com>, Baoquan He <bhe@redhat.com>, Dave Hansen <dave.hansen@linux.intel.com>, Mark Salter <msalter@redhat.com>, Aleksey Makarov <aleksey.makarov@linaro.org>, Kees Cook <keescook@chromium.org>, Andrew Morton <akpm@linux-foundation.org>, Christian Borntraeger <borntraeger@de.ibm.com>, Fabian Frederick <fabf@skynet.be>, Toshi Kani <toshi.kani@hp.com>, Dan Williams <dan.j.williams@intel.com> Cc: x86@kernel.org, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com Subject: [PATCH v1 2/2] x86/KASLR: Increase BRK pages for KASLR memory randomization Date: Mon, 8 Aug 2016 11:40:07 -0700 [thread overview] Message-ID: <1470681607-36883-2-git-send-email-thgarnie@google.com> (raw) In-Reply-To: <1470681607-36883-1-git-send-email-thgarnie@google.com> Default implementation expects 6 pages maximum are needed for low page allocations. If KASLR memory randomization is enabled, the worse case of e820 layout would require 12 pages (no large pages). It is due to the PUD level randomization and the variable e820 memory layout. This bug was found while doing extensive testing of KASLR memory randomization on different type of hardware. Signed-off-by: Thomas Garnier <thgarnie@google.com> --- Based on next-20160805 --- arch/x86/mm/init.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c index 6209289..3a27e6a 100644 --- a/arch/x86/mm/init.c +++ b/arch/x86/mm/init.c @@ -130,6 +130,14 @@ void __init early_alloc_pgt_buf(void) unsigned long tables = INIT_PGT_BUF_SIZE; phys_addr_t base; + /* + * Depending on the machine e860 memory layout and the PUD alignement. + * We may need twice more pages when KASLR memoy randomization is + * enabled. + */ + if (IS_ENABLED(CONFIG_RANDOMIZE_MEMORY)) + tables *= 2; + base = __pa(extend_brk(tables, PAGE_SIZE)); pgt_buf_start = base >> PAGE_SHIFT; -- 2.8.0.rc3.226.g39d4020
WARNING: multiple messages have this Message-ID (diff)
From: Thomas Garnier <thgarnie@google.com> To: Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>, "H . Peter Anvin" <hpa@zytor.com>, Borislav Petkov <bp@suse.de>, Joerg Roedel <jroedel@suse.de>, Dave Young <dyoung@redhat.com>, "Rafael J . Wysocki" <rafael.j.wysocki@intel.com>, Lv Zheng <lv.zheng@intel.com>, Thomas Garnier <thgarnie@google.com>, Baoquan He <bhe@redhat.com>, Dave Hansen <dave.hansen@linux.intel.com>, Mark Salter <msalter@redhat.com>, Aleksey Makarov <aleksey.makarov@linaro.org>, Kees Cook <keescook@chromium.org>, Andrew Morton <akpm@linux-foundation.org>, Christian Borntraeger <borntraeger@de.ibm.com>, Fabian Frederick <fabf@skynet.be>, Toshi Kani <toshi.kani@hp.com>, Dan Williams <dan.j.williams@intel.com> Cc: x86@kernel.org, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com Subject: [kernel-hardening] [PATCH v1 2/2] x86/KASLR: Increase BRK pages for KASLR memory randomization Date: Mon, 8 Aug 2016 11:40:07 -0700 [thread overview] Message-ID: <1470681607-36883-2-git-send-email-thgarnie@google.com> (raw) In-Reply-To: <1470681607-36883-1-git-send-email-thgarnie@google.com> Default implementation expects 6 pages maximum are needed for low page allocations. If KASLR memory randomization is enabled, the worse case of e820 layout would require 12 pages (no large pages). It is due to the PUD level randomization and the variable e820 memory layout. This bug was found while doing extensive testing of KASLR memory randomization on different type of hardware. Signed-off-by: Thomas Garnier <thgarnie@google.com> --- Based on next-20160805 --- arch/x86/mm/init.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c index 6209289..3a27e6a 100644 --- a/arch/x86/mm/init.c +++ b/arch/x86/mm/init.c @@ -130,6 +130,14 @@ void __init early_alloc_pgt_buf(void) unsigned long tables = INIT_PGT_BUF_SIZE; phys_addr_t base; + /* + * Depending on the machine e860 memory layout and the PUD alignement. + * We may need twice more pages when KASLR memoy randomization is + * enabled. + */ + if (IS_ENABLED(CONFIG_RANDOMIZE_MEMORY)) + tables *= 2; + base = __pa(extend_brk(tables, PAGE_SIZE)); pgt_buf_start = base >> PAGE_SHIFT; -- 2.8.0.rc3.226.g39d4020
next prev parent reply other threads:[~2016-08-08 18:40 UTC|newest] Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-08-08 18:40 [PATCH v1 1/2] x86/KASLR: Fix physical memory calculation on KASLR memory randomization Thomas Garnier 2016-08-08 18:40 ` [kernel-hardening] " Thomas Garnier 2016-08-08 18:40 ` Thomas Garnier [this message] 2016-08-08 18:40 ` [kernel-hardening] [PATCH v1 2/2] x86/KASLR: Increase BRK pages for " Thomas Garnier 2016-08-09 4:01 ` Borislav Petkov 2016-08-09 4:01 ` [kernel-hardening] " Borislav Petkov 2016-08-09 4:14 ` H. Peter Anvin 2016-08-09 4:14 ` [kernel-hardening] " H. Peter Anvin 2016-08-09 5:16 ` Mika Penttilä 2016-08-09 5:16 ` [kernel-hardening] " Mika Penttilä 2016-08-09 14:47 ` Thomas Garnier 2016-08-09 14:47 ` [kernel-hardening] " Thomas Garnier 2016-08-09 15:07 ` [lkp] [x86/KASLR] 20067c4c13: kernel BUG at arch/x86/mm/physaddr.c:26! kernel test robot 2016-08-09 15:07 ` [kernel-hardening] " kernel test robot 2016-08-09 16:00 ` [PATCH v1 1/2] x86/KASLR: Fix physical memory calculation on KASLR memory randomization Thomas Garnier 2016-08-09 16:00 ` [kernel-hardening] " Thomas Garnier 2016-08-09 16:03 ` Joerg Roedel 2016-08-09 16:03 ` [kernel-hardening] " Joerg Roedel 2016-08-09 16:30 ` Thomas Garnier 2016-08-09 16:30 ` [kernel-hardening] " Thomas Garnier
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=1470681607-36883-2-git-send-email-thgarnie@google.com \ --to=thgarnie@google.com \ --cc=akpm@linux-foundation.org \ --cc=aleksey.makarov@linaro.org \ --cc=bhe@redhat.com \ --cc=borntraeger@de.ibm.com \ --cc=bp@suse.de \ --cc=dan.j.williams@intel.com \ --cc=dave.hansen@linux.intel.com \ --cc=dyoung@redhat.com \ --cc=fabf@skynet.be \ --cc=hpa@zytor.com \ --cc=jroedel@suse.de \ --cc=keescook@chromium.org \ --cc=kernel-hardening@lists.openwall.com \ --cc=linux-kernel@vger.kernel.org \ --cc=lv.zheng@intel.com \ --cc=mingo@redhat.com \ --cc=msalter@redhat.com \ --cc=rafael.j.wysocki@intel.com \ --cc=tglx@linutronix.de \ --cc=toshi.kani@hp.com \ --cc=x86@kernel.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.